FAIRBANKS - Seasonality is an inescapable topic in Fairbanks. We schedule our lives around extremely short and cold winter days and the endless sun of summer, so now seems like a good time to ponder phenology, the study of seasonal biological events as they relate to annual climatic phenomena.
My research focuses on how flexibility in hibernation influences survival. My study species is the hoary marmot (Marmota caligata), a large-bodied ground squirrel easily recognized by its whistle alarm call.
My advisor at the University of Alaska Museum of the North, mammal curator Link Olson, and his students have been studying Alaska’s marmots for more than a decade and my dissertation builds on their research. Because they are diurnal, relatively conspicuous, and therefore easy to find, marmots are wonderful study organisms.
I study differences in hibernation timing between different hoary marmot populations.
Generally restricted to alpine ecosystems, hoary marmots are often seen along forested beaches in Southeast and Southcentral Alaska. These are the only locations where this is known to occur, making these beach populations a unique opportunity to study flexibility in hibernation phenology.
Thanks to Alaska’s rugged coastal terrain, beach and alpine marmots less than one mile apart can be separated by more than 3,500 feet of elevation. We have anecdotal evidence that these nearby populations differ in the amount of time spent in hibernation by more than a month, which is highly unusual.
I am interested in the health and long-term sustainability of these beach populations. If the milder conditions at sea level allow marmots to better survive and reproduce there, why are most hoary marmots and most marmot species restricted to the alpine? Are beach marmots found at sea level year round or do they migrate from the alpine seasonally? If hibernation timing is more flexible than previously thought, might that help buffer hoary marmots against rapid environmental change?
As alpine habitats continue their retreat upslope in response to climatic warming, answers to these questions become increasingly relevant.
Marmots are easy to see and hear from a distance, but trapping, marking, and re-capturing them can be arduous. Each colony behaves differently, and what works in one place isn’t guaranteed to be successful elsewhere.
Still, we were able to capture and tag 29 marmots on Wickersham Dome last summer, allowing us to refine our techniques closer to home before expanding to the beaches and alpine areas of southern Alaska.
I also use camera traps to monitor marmots. These already have provided some exciting new observations, including emergence from hibernation much earlier than previously documented. We are seeing different haying behaviors generally only associated with preparing the burrow for hibernation.
Adults on Wickersham Dome are gathering hay right before the pregnant females give birth, possibly to provide insulation for the new pups. This may reflect a local behavioral adaptation along the northernmost edge of the hoary marmot’s range, which extends south to Washington state.
We are now able to identify individuals in camera trap footage thanks to the ear tags we affixed last summer, allowing us to get information on interactions among the marmots.
For detailed information on hibernation timing, we surgically implant marmots with body temperature loggers and radio transmitters. The data loggers — about the size of three stacked dimes — record body temperature every 10 minutes for up to two years. Once retrieved, their data can be uploaded to a computer. Transmitters are necessary for relocating the marmots, which may have dispersed away from where they were trapped the previous summer.
With help from Dr. Malcolm McAdie, lead veterinarian for the Vancouver Island Marmot Recovery Project, we successfully implanted six adults on Wickersham Dome this summer. McAdie will return next summer to surgically remove the data loggers. Until then, all six marmots are happily hibernating.
It’s surprising how little is known about hoary marmot hibernation, and I feel very fortunate to have the opportunity to work with such an interesting animal and with such diverse and knowledgeable colleagues.
I’ve been enamored with Alaska since I arrived from New Mexico seven years ago to start my undergraduate at UAF, and being able to do this type of research in such a beautiful place while providing a better understanding of the world around us is why I was so happy to come back.
Katie Rubin is a graduate student at the University of Alaska Fairbanks. She’s a curatorial assistant in the mammal department at the UA Museum of the North.